Silencer

ABSTRACT

A device for silencing a flowing gas which includes a valve housing in which a valve is mounted. A separate pressure regulator is provided which is in communication with the flowing gas and which is responsive to gas pressure to thereby influence movement of a mechanical actuating device which controls movement of the valve such that the valve may be opened at least two different rates dependent upon the pressure of the flowing gas.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a silencer device for silencing of aflowing gas, comprising a valve which is arranged in a valve housingthrough which the gas is flowing.

2. Description of the Related Art

Especially in the car industry, new ways of silencing sound in, forexample, exhaust systems are investigated. One method is to deliberatelyintroduce a disturbance in the flowing gas, which causes a change in thecharacteristics of the sound in a positive way. A valve is arranged inthe flowing gas to increase the back pressure in the exhaust system andit is controlled automatically by the pressure of the gas.

Since the flow of the exhaust gases change characteristics at a certainexhaust gas pressure, depending on motor type, it is desirable that thevalve opens at different velocities at different exhaust gas pressures.At a certain pressure it is desirable that, from a sound silencing pointof view, to almost momentary open the valve in full. A choke at a highpressure and large flow rates implies large losses of effect for themotor, which of course is not desirable.

Previously known valves open at a constant or inverse exponentialvelocity, which means that the valve opens too quickly in the beginning,whereby too little silencing occur with subsequent effect losses.

An attempt to solve this problem is shown and described in the Swedishpatent application 9704221-2. Therein, a partial flow of the exhaustgases is lead to valve actuating means, which controls the opening of avalve, which is arranged in the exhaust gas flow through a silencer. Thevalve actuating means comprises two membranes and two different springsand a piston rod. At lower pressures the piston rod is drawn, againstthe biasing force of the large spring, which piston rod is connected tothe valve, into the valve actuating means so that the valve is opened.When the pressure passes a predetermined valve a passage is opened,against the biasing force of the small spring between a first and athird space so that both of the membranes are influenced at the sametime, whereby the piston rod is drawn into the valve actuating meansquicker and the valve opens quicker.

This solution is complicated and not reliable. In order to function amost accurate manufacturing is needed with components having very smalltolerances. This makes the manufacturing and also the maintenanceexpensive. Another essential problem with this solution is that it isimpossible to design the actuating means so that it will open quicklyenough after that the predetermined pressure has been achieved.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a silencer devicewhich has a simple design, is inexpensive to manufacture, reliable inuse and which has actuating means, which opens the valve nearlymomentary when a predetermined pressure is achieved.

These objects are met according to the invention by a silencer deviceaccording to the preamble, which is characterised in that the silencerdevice also comprises a separate pressure regulator, which is providedoutside of the valve housing, to which pressure regulator a conduct fromthe valve housing is leading, which leads a portion of the flowing gasto the pressure regulator, whereby, the pressure force of the gas isconvertible in the pressure regulator to a displacement motion foractuating a separate mechanical actuating means, whereby the valve (1)is openable in at least two different predetermined opening velocities,which opening velocities depend of the pressure of the gas.

Further, the actuating means gives an increased ratio after that apredetermined gas pressure has been achieved, whereby the openingvelocity increases.

According to a first embodiment of the actuating means, this shows anumber of hinged, rod like means.

Preferably, the rod like means move along a groove, which comprises atleast two differently angled guide surfaces, each guide surfacecorresponds a certain opening velocity.

According to a second embodiment of the actuating means, the valve isactuatable by the actuating means by a first length of a momentum armfrom an extended rotational axis of the valve whereby after that apredetermined gas pressure is achieved the valve is actuatable by thesecond, shorter, momentum arm from the rotational axis of the valve.

According to a third embodiment of the actuating means this shows atleast two differently sized gear wheels fixedly attached to an extendedrotational axle of the valve for successive co-operation with a gearrack each, which are actuatable by the pressure regulator.

The valve may, for example, be rotatably arranged around a rotationalaxis in the valve housing or be slided into the valve housing as aguillotine. Of course, also many other types of valves may be used.

There is a lot of advantages with the silencer device according to theinvention. For example the device is small and light weighted,especially compared to conventional silencers. Another advantage is thatyou easily may change the ratio, i.e. the opening velocity of the valve,so that the device easily may be adapted to different motors.Additionally, it is easily to provide more ratio steps, if desired.

The silencer device according to the invention may be used in manydifferent applications, such as exhaust systems and air intake systemsfor motors or other systems with flowing gas that is desirable tosilence.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiment of the invention will now be illustrated asexamples and with reference to the attached drawings.

FIG. 1 illustrates schematically the whole silencer device,

FIG. 2 illustrates a side view of a first embodiment of an actuatingmeans of the device,

FIG. 3 illustrates a front view of the first embodiment of the actuatingmeans,

FIG. 4 illustrates a side view of a valve opening series comprising theactuating means of FIGS. 2 and 3,

FIG. 5 illustrates a second embodiment of the actuating means,

FIG. 6 illustrates a side view of a valve opening series comprising theactuating means of FIG. 5,

FIG. 7 illustrates a side view of a third embodiment of the actuatingmeans,

FIG. 8 illustrates a front view of the third embodiment,

FIG. 9 illustrates a side view of a valve opening series comprising theactuating means of FIGS. 7 and 8.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In FIG. 1 a silencer device according to the present invention isillustrated, which comprises a valve 1, which is arranged in a valvehousing 2 through which the gas is flowing. A conduit 3 is lead from thevalve housing 2, through which conduit 3 a portion of the gas flows, toa pressure regulator 4. The pressure regulator 4 acts on actuating means5, which in turn regulates the opening of the valve 1.

The valve 1 has an area, which is smaller than the cross section area ofthe valve housing so that gas always may pass even when the valve is ina closed position, i.e. has its full area orthogonally to the gas flow,and has a rotational axle 6 which is rotatably arranged in the valvehousing 2.

The pressure regulator 4 comprises a membrane 7, a piston rod 8 and apressure spring 9 and converts the pressure of the gas on the membrane 7and the pressure spring 9 to a mechanical force that displaces thepiston rod 8 outwards. In case of lowered pressure the pressure spring 9returns so that the piston rod is drawn into the pressure regulator 4again. The piston rod 8 acts on the actuating means 5.

The actuating means 5 may be designed in many different ways. Threeembodiments will be described hereafter. FIG. 2 illustrates a firstembodiment of the actuating means 5 as seen from the side. The actuatingmeans 5 comprises three rods, which are hingably attached to the ends ofeach other. A first rod 10 is hingably attached to the piston rod 8 ofthe pressure regulator 4 with its first end and with its second end to afirst end of a second rod 11. The second rod 11 is in turn hingablyattached with its second end to a first end of a third rod 12. The thirdrod 12 is fixedly attached, orthogonally to, with its second end to therotational axle 6 of the valve 1, see FIG. 3.

Between the second end of the first rod 10 and the first end of thesecond rod 11 a hinge 13 is provided. This hinge 13 has portions thatprotrude substantially orthogonally to the lengthwise extension of therods 10, 11, see FIG. 3. A housing is fixedly attached to the exteriorof the valve housing 2. The rods 10, 11, 12 lead through the housing 14.In the side walls of the housing 14, grooves 15 comprising guidesurfaces are arranged in which the protruding portions of the hinge 13may move. The grooves 15 are divided into two straight portions, whichare angled to each other.

When the gas pressure increases the piston rod 8 of the pressureregulator 4 is displaced outwards, see FIG. 4, and thereby the first rod10 is displaced so that the protruding portions of the hinge 13 slidesalong the first portions of the grooves, whereby also the second andthird rod 11, 12 are influenced. The third rod 12 turns the valve 1,i.e. opens it, due to the fixed attachment between the third rod 12 andthe rotational axle 6. This is carried out in a uniform velocity as longas the protruding portions of the hinge 13 slides along the firstportions of the grooves 15.

When a certain pressure has been reached and the valve 1 has opened acertain percentage, the protruding portions of the hinge 13 has reachedthe transition between the first and the second portions of the grooves15, whereupon the ratio is changes and the valve 13 opened with highvelocity when the protruding portions of the hinge 13 slides along thesteep second portions of the grooves 15. The valve 1 then opens almostmomentary.

Preferably there are grooves 15 provided on both of the sides of therods 10, 11, 13 so that a stable movement may occur along the grooves 15but of course it is possible to have only one groove. By changing thelength of the rods and/or the angle of the grooves the ratio will changeand thereby the opening velocity of the valve 1. If so desired, alsofurther ratio steps may be inserted by inserting further angled portionsof the groove.

In FIG. 5 a second embodiment of the actuating means 5 is illustrated,which comprises four rods which move in a calculated path when acted onby the piston rod 8 of the pressure regulator 4. A first rod 16 ishingably attached at its first end to the piston rod 8 and at its secondend to a first end of a second rod 17. The second rod 17 is at itssecond end hingably attached to a first end of a third rod 18. The thirdrod is fixedly attached, orthogonally to, at its second end to therotational axle 6 of the valve 1. A fourth rod 19 is in one of its endsfixedly attached orthogonally outwards from the third rod 18 and is inthe same plane as the other rods 16, 17, 18.

When the piston rod 8 is displaced out of the pressure regulator 4, seeFIG. 6, the first rod 16 is displaced and the second rod 17 is inclined,which in turn influence the third rod 18 so that the valve 1 turns, i.e.opens. The increase in pressure displaces the piston rod 8, which inturn influence the first to the third rod at a certain ratio, whichgives a certain opening velocity.

When the pressure exceeds a certain value and the valve 1 has beenopened to a certain percentage, the ratio is changed due to the factthat the free end of the fourth rod 19 comes into contact with thesecond rod 17. Then the influence of the actuating means 5 on the valve1 is transmitted by a shorter momentum arm, which causes the valve 1 toopen much faster, preferably almost momentary.

Depending on how the lengths of the rods are designed and where theattachments are positioned it is possible to achieve desired ratios.Preferably, the second rod 17 is planar at the surface where the fourthrod 19 comes into contact, but the second rod 17 may instead have asquare or rectangular cross-section.

In FIG. 7 a third embodiment of the actuating means 5 is shown from theside, which comprises a large 20 and a small 21 gear wheel, an upper 22and a lower 23 slide rod and two attachments 24. The attachments 24 arearranged on the exterior of the valve housing 2 and are provided withrecesses in which the two slide rods 22, 23 may slide at the same timeas they are supported by the attachments 24. The piston rod 8 from thepressure regulator 4 is fixedly attached to a slide rod unifying means25 so that both the slide rods 22, 23 are influenced, at the same time,by the piston rod 8 at pressure changes and slides in the attachments24.

On the upper slide rod 22 there is a gear rack portion 26, so that theslide rod partially functions as a gear rack, which may co-operate withthe small gear wheel 21 and on the lower slide rod 23 there is a gearrack portion 27, so that the slide rod partially functions as a gearrack, which may co-operate with the large gear wheel 20. The large andsmall gear wheel 20, 21 are fixedly attached to the rotational axle 6 ofthe valve 1, see FIG. 8. The slide rods 22, 23 are arranged slightlydisplaced sideways so that they are positioned under each gear wheel 21,20, respectively.

When the gas pressure increases the large gear wheel meshes with thegear rack portion 27 at the lower slide rod 23, see FIG. 9, so that thevalve 1 opens with a low velocity. When a predetermined pressure hasbeen reached and the valve 1 has opened a predetermined percentage, theslide rods 22, 23 have been displaced so much that the large gear wheel20 loses contact with the gear rack portion 27 on the lower slide rod 23at the same time as the small gear wheel 21 meshes with the gear rackportion 26 of the upper slide rod 22. Since the radius of the small gearwheel is smaller than the radius of the large gear wheel 20 the ratiochanges so that the valve 1 opens very quickly at a pressure increase.

Also in this embodiment it is easy to simply change the ratio bychanging the dimensions of the gear wheels. If further ratio steps aredesired, further gear wheels with co-operating gear rack rods may beprovided.

These embodiments have been shown in combination with a valve, which isrotatably arranged around a rotational axis in the valve housing. Ofcourse, also many other types of valves may be used, for example, avalve which is slided into the valve housing as a guillotine.

What is claimed is:
 1. A silencer device for silencing a flowing gas,comprising a valve (1), which is arranged in a valve housing (2) throughwhich the gas is flowing, a separate pressure regulator (4) providedexterior of the valve housing (2), a conduit (3) for communicating gasflowing to the valve housing (2) to the pressure regulator (4) so that aportion of the gas flows to the pressure regulator, whereby a pressureforce of the portion of gas is convertable in the pressure regulator (4)to a displacement motion for influencing of a separate mechanicalactuating means (5), by means of a piston rod (8) which is displaceableoutwards of the pressure regulator (4) for acting on the actuating means(5), which in turn makes the valve (1) openable at at least twodifferent predetermined opening velocities and wherein the actuatingmeans (5) has an increase ratio after each of at least one predeterminedgas pressure has been reached, whereby the opening velocity of the valve(1) increases for each ratio increase.
 2. The silencer device accordingto claim 1 wherein the actuating means (5) has at least two differentlysized gear wheels (20, 21) fixedly attached to an extended rotationalaxle (6) of the valve (1) for successive co-operation with a gear rackrod (22, 23) each which are influenced by the pressure regulator (4). 3.The silencer device according to claim 1, wherein the actuating means(5) a number of hinged rod means (10, 11, 12, 13, 16, 17, 18, 19). 4.The silencer device according to claim 3, wherein the rod means (10, 11,12, 13) are movable along a groove (15) which comprises at least twodifferently angled guide surfaces, whereby each guide surfacecorresponds to a different opening velocity.
 5. The silencer deviceaccording to claim 3, wherein the valve (1) is influenced by theactuating means (5) by means of a first momentum arm from an extendedrotational axle (6) of the valve (1) and whereby when the predeterminedgas pressure has been reached, the valve (1) is influenced by theactuating means (5) by a second momentum arm, which is shorter than thefirst, from the rotational axle (6) of the valve (1).
 6. A silencerdevice for silencing a gas flowing through a conduit, comprising; avalve (1), which is arranged in a valve housing (2) communicating withthe conduit through which valve housing the gas is flowing, a pressureregulator (4) exterior of the valve housing (2), a tap conduit (3) fordirecting a portion of the gas flowing through the conduit to thepressure regulator (4), whereby pressure of the gas is convertable inthe pressure regulator (4) to a displacement motion for moving aseparate mechanical actuating means (5) the valve (1) being openable atat least two different opening velocities dependent on the pressure ofthe gas by means of the separate mechanical actuating means (5), and theactuating means (5) having an increased motion ratio after apredetermined gas pressure has been reached in the pressure regulator,whereby the opening velocity of the valve (1) increases.